We have recently gone LIVE successfully with S4 HANA 1511 accounting modules with one vendor while now we are implementing core HCM on premise with another vendor, though we have given separate dev client for their sandbox tests, they will have to transfer configuration to existing golden client and transport later to existing QAS and PROD.

Do we need to have separate clients for this or we can use the same clients? Any risks? Whats is the best practice and what if we need some configuration copy from 000 to golden client, will it affect any existing customisations?